Validate if a given string is numeric.
Some examples:
"0" => true" 0.1 " => true"abc" => false"1 a" => false"2e10" => true解法真是非常呆，不過直覺也不是壞事
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 | bool isNumber(char* s) { int len=strlen(s); int i; bool havedot=false; bool havee=false; bool havespace=false; bool havenum=false; bool havesymbol=false; for(i=0; i<len; i++) { if(s[i]<0x30 || s[i]>0x39) { if(' ' == s[i]) { if(havenum || havee || havedot || havesymbol) { havespace = true; } } else if('.' == s[i]) { if(havee || havedot || havespace) { return false; } else { havedot = true; } } else if('e' == s[i]) { if(havee || !havenum) { return false; } else { havee = true; havenum = false; havesymbol = false; } } else if('+' == s[i] || '-' == s[i]) { if (havee) { if (havesymbol || havenum) { return false; } } else { if (havesymbol || havenum || havedot) { return false; } } havesymbol = true; } else { return false; } } else { if(havespace) { return false; } havenum = true; } } return havenum; } |
